A card cheat is threatened with exposure into joining a criminal enterprise that Sherlock Holmes believes is controlled by Professor Moriarity.
Sherlock Holmes
Dr. John Watson
Mrs. Hudson
Ronald Adair
Kathleen Adair
Prof. Robert Moriarty / Col. Henslowe
Thomas Fisher
Tony Rutherford
Inspector Lestrade
Marston, the butler
Colonel Sebastian Moran
No. 16
J.J. Godfrey
